Problem: $ { \left[\begin{array}{rr}{2} & {4} \\ {-1} & {-2} \\ {4} & {2}\end{array}\right]+\left[\begin{array}{rr}{2} & {2} \\ {-1} & {0} \\ {2} & {4}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rr}{2}+{2} & {4}+{2} \\ {-1}+{-1} & {-2}+{0} \\ {4}+{2} & {2}+{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{4} & {6} \\ {-2} & {-2} \\ {6} & {6}\end{array}\right]}$